Show HN: Marelleo, an open-source story box I built for my kids using ESP32 (zebra.rodeo)

194 points by foOg •

Hi Hacker News!

I wanted to give my three kids a screenless story box (inspired by the Toniebox gesture) but I was deeply annoyed by the closed ecosystem and subscription-like models of commercial alternatives.

So, despite knowing absolutely nothing about electronics three months ago, I decided to build one myself using an ESP32, an NFC reader, and a Bambu Lab printer. I learned everything the hard way, from accidentally creating short circuits to routing 491 tracks by hand on my first custom PCB with KiCad (and using Claude to double-check my math).

The box serves its own local web page to upload MP3s/M4As, streams web radios, and handles self-updates over Wi-Fi with a built-in safety net in case the network stack crashes.

Everything is fully open-source (firmware, KiCad files, 3D models under MIT license) on GitHub: link in the article

I’d love to hear your thoughts, feedback on the PCB routing, or answer any questions about the build!

Please don't use any LLM to write about your projects in the future.

https://martinfowler.com/bliki/LLM-Voice.html

I'm planning something like this. I already have Home Assistant with Music Assistant working, so playing radio and music and audiobooks in rooms are already possible with my phone. I plan to add ESPHome device with NFC reader to trigger plays so it's easy for the kids to use it. Just need to find where I left my roll of 50 NFC stickers.

One suggestion: In my opinion, kids nowadays are very familiar with charging devices with USB-C. Powering the device with USB-C will be much easier. Worse case scenario, I'll use some small portable power bank and place it inside.

Très cool ! Si tu es sur Paris et que tu veux lancer un petit workshop pour apprendre aux autres à le faire je suis partant haha

Using LLMs to write comments on this site is against the rules.

It‘s awesome, thanks and your progress from breadboard to finished project is amazing! Don‘t let all the complaints here keep you from building and sharing.

You could consider replacing the potentiometer with an encoder that has no fixed range and can’t be broken by turning it too much.

Hey, nica project! Can you add the pcb schematics and the Fusion 360 source files for the enclosure? Thanks!

First off - well done, this is amazing. Secondly, it's a fascinating read how you basically figured it out, one mistake at a time, like not connecting or fastening the battery correctly. This is the way! We make mistakes and figure things out in our journey to make something interesting, and learn along the way.

I am mostly into software my whole life. I want to dabble with hardware and electronics in the future and this post taught me many things that’ll be very useful when I do.

Tnx for writing every bit of the building process in an easy to understand way and also open sourcing it.

I liked the look of your box too. Keep up!

Btw I just discovered https://confetti.build and YC backs it. Have a look, you’ll love it.

This seems like an interesting project but the Claude writing rubs me the wrong way. I couldn't finish it, unfortunately, but props for building it!

I absolutely hate AI writing as well, but I suspect since the author is French, and the underlying code in their GitHub project [1] uses a lot of French naming, that it was more of a translation aid.

[1] https://github.com/Zebra-Rodeo/marelleo

Yeah I think that's what happened. Still a bit unfortunate though for presenting such a nice project.

The French is pretty much word-for-word the same as the English, so the Claudeisms didn't come from translation. It's all the same LLM output.

"You’re not buying a player, you’re buying a subscription dressed up as a wooden toy. And that genuinely annoys me."

had to stop reading from that point onwards.

There are some ugly tell tale signs of AI writing here: No screen, no menu, no parent [...]

You’re not buying a player, you’re buying a subscription [...]

I particularly hate the first one, don't AI sloppers notice how horrible it is to read "No x, no y, no z"?

Great job, this is really inspiring. How do you create the content for each of your kids?

Probably the same way he did the entire project and the web page : with AI.

This is really sweet. Reminds me of an old client I worked for called Museum in a Box (https://museuminabox.org/). It was started by George Oates (ex. Flickr).

3D printed figurines on top of a box which would activate museum style narration and multimedia. It was based on a Raspberry PI though which is different from this project but in many ways, it was the same.

This is an excellent project! Congrats and thanks for sharing! (LLM writing notwithstanding)

I wonder if it would be a good base to create a kids phone / yogurt-cup telephone: no screen, no keyboard, just a box and figurines, and to call someone up you put the figurine on the box. It could be boxes-only (only people with a box can call or be called) or it could be more general: kids only have boxes and figurines, but the machine is able to call actual phones.

I think even as an adult I would enjoy that.

This is incredible - I definitely wanted to do the same for my kid once he gets a bit older so I'm bookmarking this.

I read through the whole thing and found it informative, LLM or not. To all AI low effort naysayers I think for a working parent this maybe would not have been possible to write in reasonable time without the aid of Claude.

Kudos to the author.

_deleted_

I loved the article. This is a project I've been wanting to do myself.

Fast dopamin? Did you read the article? I did. I think he mentions spending 3 months on this. Going from zero to hero on a project like this failed on 3 attempts, because figuring stuff out from forums alone is just way too hard.

Sorry man, but I really don't see your problem. A guy made something and wrote an article about making it. Did LLMs help? Yes, he's quite open about that. So what?!

TFA mentions this product in the first paragraph and how much the product sucks as the whole motivation for the project.

Wow thanks for the info about the toniebox reverse engineering!

My kids got offer a toniebox this year, and when discovering the product I was so upset about this locked and privacy nightmare I brought it back to the seller for a refund and started to look for alternatives (got time, still very young). Will check it out!

Why the gatekeeping? It’s their choice how they spend their time and tokens, and nobody is forced to use it.

As long as they had fun and enjoyed the process, that’s what counts. Enterprise software deployment is a different story, of course.

What are you talking about? "I hate him"? He literally learnt how to build an interactive electronic toy for his children and then put in the effort to share it online. You didn't even take the time to read it because he talks about the Toniebox at the very start of article.

So he used AI to do the write up? He also references paying in Euros so English is probably not his first language. I think you need to calm down and critically examine your priorities.

love it! incredible! and you got it to work at first attempt! i really need to start to find time to my own unfinished..or not started projects that are little bit similiar. annd you made your own pcb?! what the actual .. i was thinking that's something you'll need to have years of experience and 5 revisions

Very educative, thanks for sharing the story!

Nice work. Although I'd probably had used one of the newer esp32 from seeed Studio with integrated battery pads (unfortunately the BatteryPal from PNLabs is still in the making). A DFPlayer Mini might also habe saved some time...

There also is a german project called Tonuino, which is quite similar and has lots of examples and documentation - they even designed a custom PCB which unfortunately is no longer available:

https://github.com/tonuino/TonUINO-TNG

Another rasperry focussed project that has a web interface is Phoniebox:

https://phoniebox.de/index-en.html

There also is a toniebox hack, which lets you setup a self-hosted content server:

https://gt-blog.de/toniebox-hacking-how-to-get-started/

Another one worth a look is ESPuino (also a german project). Custom PCBs are still available for that one afaik.

https://github.com/biologist79/ESPuino

Not mentioned in the last link is TeddyCloud (https://tonies-wiki.revvox.de/docs/tools/teddycloud/), which enables you do keep regular Tonie functionality and add your own content on top.

Nice project but the writing smells so much of LLM that I didn't manage to finish the article

I read it through. There have always been articles, even before LLMs, that exceed your personal "drivel" threshold, that you abandon. That's ultimately what matters, do you want to keep reading or not.

but now the drivel all sounds the same, a uniform pablum changing slightly with every model update.

That was much rarer though. Now the sad norm is someone's idea, AI code with AI docs and AI "article".

I'm not spending my time on reading something someone claims it's not important enough to write or at least edit. At most I'll send my LLM to check if there's anything useful in the code (but i don't reuse it because I know my harness and tests are sound, not sure about someone so lazy).

Inspiring product, thank you for sharing. How easy it would be to convert it so it accepts normal AA batteries ?

I agree with the commenters who were jarred by the heavy use of LLMisms -- the writing was genuinely painful to read. What a really fun project though!

Props for seeing it through a debugging phase, it can really be worrying when you get your boards and they just don't work.

Love that it's open source, nice alternative to the closed boxes like Toniebox. How do the kids pick a story, NFC cards or buttons? And how long does the battery last on the ESP32?

Toniebox has a handful of patents on parts of the functionality. Not that it matters here, just a heads-up in case anyone thinks of productizing something like it :)

Things like detecting a figurine placed on top of the box with RFID/magnet and then doing something.

https://patents.justia.com/assignee/tonies-gmbh if anyone was curious.

It’s odd because the first part sounds like it was written or at least copy-edited by a human who started getting tired and gave up, and as it goes on it sounds more and more sloppish. Nice project though.

This is nearly the exact project that I have been working on! Exactly the same reasons :) Congrats on finishing up. I need to go back on this asap.

ai garbo

One thing I will say about the Yoto player is that there is an API: https://yoto.dev/api/ . You can do all sorts of things: get button presses over a MQTT queue, redirect the player to download audio from a server that _you_ host, and even dynamically update the playlist behind the scenes. Oh, and add static or animated GIFs for display on the device. It's really fun to mess around with - I created a travelogue for my daughter when I was away for a work trip a couple of months ago…

Omg this is amazing and solves so many of the issues I have with Yoto!

Agree, we have Yoto and while I have bought some cards… their “make your own cards” system is pretty much open to whatever you want to do.

They seem like a solid company

Awesome project if you wanted to build it.

But the problem is invented - if you invested a fraction of the time to research, you would see that custom tonies sell for like $8 a piece for up to 90min of your audio, or you can diy all of it by getting the ICODE SLIX-L chips for like $1.5 a piece and adding any content by accessing the internal micro sd card.

This is one of the most interesting projects I have seen on hn lately. Congratulations

Soon your kids will grow up and you will miss not having spent mote time with them. You are their story box.

ESP32 and Claude give so many possibilities for small projects that solve one thing at time in our lifes. I had created with claude a simple wifi alarm, just for avoiding having my mobile at home. A esp32 + df player + sd, everything configured via a wifi page and fixed on the wall with a phone charger.

I can imagine doing a couple dozen projects like that over a year can improve daily life in a significant level